Bone Marrow Aplasia in Childhood Leukaemia

Summary Six of 21 children with blast cell leultaemia were found at post‐mortem to have a hypoplastic or aplastic bone marrow. Leukaemic infiltrations were found in the organs of all the cases with a hyperplastic marrow, but were present in only one of the cases in the aplastic group and are limited to the meninges. The cause of aplasia of the bone marrow in leukaemis is discussed, particularly with regard to the possible influence of the folic acid antagonists. In two of the cases the bone marrow biopsies were indicative of an aplastic course from the start. The treatment in these cases seems to have reduced the activity of the bone marrow still further. In one case the aplasia developed during prolonged treatment with folic acid antagonists; a causal relationship is, however, uncertain. In the remaining three cases there was a haematological response after treatment with folic acid antagonists. At autopsy changes that could have been due to lack of folic acid were found in the organs.